Apparatus and method of controlling electronic parking brake

ABSTRACT

An apparatus and a method of controlling an electronic parking brake are provided to prevent collision with a preceding vehicle by generating additional target clamping force through interoperation with an advanced emergency brake system (AEBS) to improve performance of the AEBS. The apparatus includes an electric parking brake (EPB) that generates target clamping force and an information collector that collects a primary warning signal and a primary demanded deceleration by interoperating with an AEBS. A controller operates the EPB to perform a preparation process for braking when the primary warning signal is collected and perform braking until a primary actual deceleration corresponding to the primary demanded deceleration is measured when the primary demanded deceleration is collected.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims the benefit of priority toKorean Patent Application No. 10-2015-0147440, filed on Oct. 22, 2015 inthe Korean Intellectual Property Office, the disclosure of which isincorporated herein in its entirety by reference.

TECHNICAL FIELD

The present disclosure relates to an apparatus and a method ofcontrolling an electronic parking brake, and more particularly, to atechnology capable of effectively preventing collision with a precedingvehicle by generating additional target clamping force throughinteroperation with an advanced emergency brake system (AEBS) to improveperformance of the AEBS.

BACKGROUND

Generally, an electric parking brake (EPB) is a brake that is lockedduring stopping of a vehicle and is automatically unlocked when startingthe vehicle. In other words, the electronic parking brake is locked eventhough a driver does not engage a brake pedal during a period in whichthe vehicle is stopped and is automatically unlocked when the driverengages only the brake pedal in the state in which the brake is lockedwhen the vehicle starts, such that the vehicle starts as it is.Therefore, the electronic parking brake improves convenience of thedriver on a slope (e.g., inclined road), when traffic congestion issevere, or the like.

The electronic parking brake generates appropriate target clamping forceby pulling a brake wire through a brake operating motor based on aresult obtained by synthesizing state information such as a load of thevehicle, a gradient of a parking place, and the like, and a driver'sintention. In other words, target clamping force of the vehicle isdetermined based on tension of the brake wire that operates the brake,and a tension measuring sensor that senses the tension of the brake wireis used to determine whether the brake wire is pulled by appropriatetension through the brake operating motor.

The tension measuring sensor transfers the tension of the brake wire toa controller (an EPB, an electronic control unit (ECU), or the like) toallow the tension of the brake wire to be appropriately adjusted.Meanwhile, an advanced emergency brake system (AEBS) senses apossibility of collision with a preceding vehicle to provide a primarywarning to the driver, and automatically decelerates the vehicle toavoid the collision with the preceding vehicle while providing asecondary warning for informing the driver of automatic braking when areaction of the driver is not present or the collision is determined tobe inevitable. Since the AEBS according to the related art operates amain brake to brake the vehicle, when maximum target clamping force ofthe main brake is insufficient, particularly, for a commercial vehicle,collision with the preceding vehicle may not be prevented.

SUMMARY

Accordingly, the present disclosure provides a technology of assistingin an advanced emergency brake system (AEBS) using an electronic parkingbrake to solve the problem described above. In other words, an aspect ofthe present disclosure provides an apparatus and a method of controllingan electronic parking brake capable of effectively preventing collisionwith a preceding vehicle by generating additional target clamping forcethrough interoperation with an AEBS to improve performance of the AEBS.

Objects of the present disclosure are not limited to the above-mentionedobject, and other objects and advantages of the present disclosure thatare not mentioned may be understood by the following description andwill be more clearly appreciated by exemplary embodiments of the presentdisclosure. In addition, it may be easily appreciated that objects andadvantages of the present disclosure may be realized by means mentionedin the claims and a combination thereof.

According to an exemplary embodiment of the present disclosure, anapparatus of controlling an electronic parking brake may include: anelectric parking brake (EPB) configured to generate target clampingforce; an information collector configured to collect a primary warningsignal and a primary demanded deceleration by interoperating with anAEBS; and a controller configured to operate the EPB to perform apreparation process for braking when the primary warning signal iscollected by the information collector and perform braking until aprimary actual deceleration that corresponds to the primary demandeddeceleration is measured when the primary demanded deceleration iscollected by the information collector.

According to another exemplary embodiment of the present disclosure, amethod of controlling an electronic parking brake may include:collecting, by an information collector, a primary warning signal froman AEBS; performing, by a controller, a preparation process for braking;collecting, by the information collector, a primary demandeddeceleration from the AEBS; and operating, by the controller, an EPB toperform braking until a primary actual deceleration corresponding to theprimary demanded deceleration is measured.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentdisclosure will be more apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings.

FIG. 1 is a block diagram illustrating an apparatus of controlling anelectronic parking brake according to an exemplary embodiment of thepresent disclosure;

FIG. 2 is an illustrative view illustrating a relationship between ademanded deceleration and an actual deceleration used in an exemplaryembodiment of the present disclosure; and

FIG. 3 is a flow chart illustrating a method of controlling anelectronic parking brake according to an exemplary embodiment of thepresent disclosure.

DETAILED DESCRIPTION

It is understood that the term “vehicle” or “vehicular” or other similarterm as used herein is inclusive of motor vehicles in general such aspassenger automobiles including sports utility vehicles (SUV), buses,trucks, various commercial vehicles, watercraft including a variety ofboats and ships, aircraft, and the like, and includes hybrid vehicles,electric vehicles, combustion, plug-in hybrid electric vehicles,hydrogen-powered vehicles and other alternative fuel vehicles (e.g.fuels derived from resources other than petroleum).

Although exemplary embodiment is described as using a plurality of unitsto perform the exemplary process, it is understood that the exemplaryprocesses may also be performed by one or plurality of modules.Additionally, it is understood that the term controller/control unitrefers to a hardware device that includes a memory and a processor. Thememory is configured to store the modules and the processor isspecifically configured to execute said modules to perform one or moreprocesses which are described further below.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. As used herein, the term “and/of”includes any and all combinations of one or more of the associatedlisted items.

Unless specifically stated or obvious from context, as used herein, theterm “about” is understood as within a range of normal tolerance in theart, for example within 2 standard deviations of the mean. “About” canbe understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%,0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear fromthe context, all numerical values provided herein are modified by theterm “about.”

Furthermore, control logic of the present invention may be embodied asnon-transitory computer readable media on a computer readable mediumcontaining executable program instructions executed by a processor,controller/control unit or the like. Examples of the computer readablemediums include, but are not limited to, ROM, RAM, compact disc(CD)-ROMs, magnetic tapes, floppy disks, flash drives, smart cards andoptical data storage devices. The computer readable recording medium canalso be distributed in network coupled computer systems so that thecomputer readable media is stored and executed in a distributed fashion,e.g., by a telematics server or a Controller Area Network (CAN).

The above-mentioned objects, features, and advantages will become moreobvious from the following description described below in detail withreference to the accompanying drawings. Therefore, those skilled in theart to which the present disclosure pertains may easily practice atechnical idea of the present disclosure. Further, in describing thepresent disclosure, when a detailed description of a well-knowntechnology associated with the present disclosure may unnecessarily makethe gist of the present disclosure unclear, it will be omitted.Hereinafter, exemplary embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram illustrating an apparatus of controlling anelectronic parking brake according to an exemplary embodiment of thepresent disclosure. As illustrated in FIG. 1, the apparatus ofcontrolling an electronic parking brake according to an exemplaryembodiment of the present disclosure may include an electric parkingbrake (EPB) 10, an information collector 20, a controller 30, and adisplay 40. The controller 30 may be configured to operate the EPB 10,the information collector 20 (e.g., a sensor), and the display 40.

In particular, the EPB 10, which is an electronic parking brake,operates to prevent a driver from engaging a brake pedal (e.g., exertpressure onto the pedal) by automatically generating target clampingforce when stopping a vehicle, may be configured to assist in anadvanced emergency brake system (AEBS) under an operation of thecontroller 30 to generate additional target clamping force in thepresent disclosure. Although the EPB 10 has been described as an exampleof the means assisting in the AEBS to generate the additional targetclamping force in an exemplary embodiment of the present disclosure, anydevice having a function that may brake or decelerate the vehicle underan operation of the controller 30 may be used.

The EPB 10 may include a brake operating motor configured to pull abrake wire to allow a brake shoe to contact a contact point of a brakedrum, and a sensor configured to sense tension of the brake wire. Forreference, the AEBS may be configured to sense or detect a possibilityof collision with a preceding vehicle to generate a primary warningsignal, and perform vehicle braking to avoid the collision with thepreceding vehicle while generating a secondary warning signal thatinforms the driver of automatic braking when a reaction of the driver isnot present (e.g., the driver does not take an action in response to thewarning) or the collision is inevitable.

Further, a gap may be generated between a deceleration (hereinafter,referred to as a demanded deceleration) demanded by the AEBS and anactual behavior (hereinafter, referral to as an actual deceleration) ofthe vehicle. Hereinafter, a relationship between the demandeddeceleration and the actual deceleration will be described withreference to FIG. 2. In FIG. 2, a vertical axis indicates the demandeddeceleration, a horizontal axis indicates a time T, ‘210’ indicates agraph for the demanded deceleration, and ‘220’ indicates a graph for theactual deceleration of the vehicle.

When a primary demanded deceleration is about −2.6 m/s² as an example, atime T1 is normal when within about 150 ms, but was 430 ms as anexperiment result. In other words, an actual deceleration thatcorresponds to the primary demanded deceleration should be measuredwithin 150 ms, but was measured at 430 ms. Accordingly, the dataindicates that insufficient target clamping force was supplied, andthus, the vehicle may not be stopped or decelerated by a desired amountwithin a desired period of time. This is complemented in the presentdisclosure.

When a secondary demanded deceleration is about −6 m/s² as an example, atime T2 is normal when within about 330 ms, but was 470 ms as anexperiment result. In other words, an actual deceleration thatcorresponds to the secondary demanded deceleration should be measuredwithin 330 ms, but was measured at 470 ms. Accordingly, the dataindicates that insufficient target clamping force was supplied, andthus, the vehicle may not be decelerated by a desired amount within adesired period of time. This is complemented in the present disclosure.

Furthermore, the information collector 20 of present disclosure may beconfigured to collect information by interoperating with the AEBS.Particularly, the information collector 20 may be configured to collectthe primary warning signal, the primary demanded deceleration, and thesecond demanded deceleration generated by the AEBS. The informationcollector 20 may be configured to collect the information by directlyinteroperating with the AEBS or collect the information via a vehiclenetwork. The vehicle network may include a controller area network(CAN), a local interconnection network (LIN), a FlexRay, a mediaoriented system transport (MOST), and the like. The controller 30 maythen be configured to perform a general control to operate therespective components described above.

Particularly, the controller 30 may be configured to perform apreparation process to execute rapid braking when the primary warningsignal is collected by the information collector 20. In other words, thecontroller 30 may be configured to operate the EPB 10 to allow the brakeshoe to approach the contact point of the brake drum when the primarywarning signal is collected. Particularly, the brake shoe may furthermove by about 10% due to inertia even though a current is blocked due tocharacteristics of the brake operating motor, Therefore, the controller30 may be configured to operate the EPB 10 in consideration of this andthe brake shoe may approach the brake drum as closely as possiblewithout generating substantial target clamping force.

In addition, the controller 30 may be configured to operate the EPB 10to perform braking until a primary actual deceleration that correspondsto the primary demanded deceleration is measured, when the primarydemanded deceleration is collected by the information collector 20. Theprimary actual deceleration may be set to about 90% of the primarydemanded deceleration to offset an exceeding deceleration (e.g., anexceeding actual deceleration) generated by inertia of a main brake.Particularly, the exceeding deceleration corresponds to ‘01’ in FIG. 2.Accordingly, a section T1 of FIG. 2 may be reduced to 150 ms or less.

Further, the controller 30 may be configured to operate the EPB 10 toperform braking until a secondary actual deceleration that correspondsto the second demanded deceleration is measured, when the secondarydemanded deceleration is collected by the information collector 20. Thesecondary actual deceleration may be set to about 90% of the secondarydemanded deceleration to prevent a phenomenon in which a wheel isinstantaneously locked by the exceeding deceleration (e.g., theexceeding actual deceleration) generated by the inertia of the mainbrake. Particularly, the exceeding deceleration corresponds to ‘02’ inFIG. 2. Accordingly, a section T2 of FIG. 2 may be reduced to 330 ms orless.

The controller 30 may additionally be configured to operate the EPB 10to perform a slow ramp up (SRU) function when the secondary actualdeceleration is converged within a threshold range (±A1) in relation tothe second demanded deceleration. For example, when the secondarydemanded deceleration is about −6 m/s², the secondary actualdeceleration, which is a reference for stopping the braking, may be setto about −5.4 m/s², and when the threshold range is about ±0.12 m/s² inrelation to −6 m/s², the controller 30 may be configured to operate theEPB 10 to perform the SRU function when the secondary actualdeceleration is between about −6.12 m/s² and −5.88 m/s².

In particular, the SRU, which is a function of the EPB 10 increasingtarget clamping force, increases the target clamping force to preventcollision when a risk of the collision is maintained due to an overloadof a commercial vehicle or a limitation of the main brake. In addition,the SRU increases additional target clamping force at a gentle gradient(e.g., a subtle gradient), thereby making it possible to minimizebraking impact of the driver. However, when a vehicle dynamic control(VDC) (not illustrated) mounted within the vehicle requests stop of theSRU function to perform a direct control, the VDC has a priority, andthe EPB 10 may be configured to terminate the SRU function. Inparticular, even though the SRU function is stopped, the target clampingforce of the EPB 10 may be maintained as a value at the moment at whichthe SRU function is stopped.

Further, the display 40 may be configured to display general informationregarding an operation of the EPB 10. Although an example in which theinformation collector 20 and the controller 30 are implemented asseparate components has been described in an exemplary embodiment of thepresent disclosure, a controller (not illustrated) of the EPB 10 may beimplemented to perform both of a function of the information collector20 and a function of the controller 30.

FIG. 3 is a flow chart illustrating a method of controlling anelectronic parking brake according to an exemplary embodiment of thepresent disclosure. First, the information collector 20 may beconfigured to collect the primary warning signal from the AEBS (301).Then, the controller 30 may be configured to perform a preparationprocess for braking (302). The preparation process indicates a processof allowing the brake shoe of the EPB 10 to approach to the contactpoint of the brake drum. The information collector 20 may then beconfigured to collect the primary demanded deceleration from the AEBS(303).

Further, the controller 30 may be configured to operate the EPB 10 toperform the braking until the primary actual deceleration thatcorresponds to the primary demanded deceleration is measured (304). Theinformation collector 20 may be configured to collect the secondarydemanded deceleration from the AEBS (305). The secondary demandeddeceleration may be a maximum demanded deceleration. Then, thecontroller 30 may be configured to operate the EPB 10 to perform thebraking or decelerating until the secondary actual deceleration thatcorresponds to the secondary demanded deceleration is measured (306).Further, the controller 30 may also be configured to operate the EPB 10to perform the SRU function when the secondary actual deceleration isconverged within a threshold range in relation to the second demandeddeceleration. In particular, when a stop request is received from theVDC, the controller 30 may be configured to operate the EPB 10 to stopthe SRU function.

Meanwhile, the method of controlling an electronic parking brakeaccording to an exemplary embodiment of the present disclosure asdescribed above may be created by a computer program. In addition, codesand code segments configuring the computer program may be easilyinferred by a computer programmer skilled in the related art. Further,the created computer program is stored in a computer-readable recordingmedium (information storing medium) and is read and executed by acomputer to implement the method of controlling an electronic parkingbrake according to an exemplary embodiment of the present disclosure.Further, the computer-readable recording medium includes all types ofrecording media that are readable by the computer.

As described above, according to the exemplary embodiment of the presentdisclosure, the additional target clamping force may be generatedthrough interoperation with the AEBS to improve performance of the AEBS,thereby making it possible to prevent the collision with the precedingvehicle.

Hereinabove, although the present disclosure has been described withreference to exemplary embodiments and the accompanying drawings, thepresent disclosure is not limited thereto, but may be variously modifiedand altered by those skilled in the art to which the present disclosurepertains without departing from the spirit and scope of the presentdisclosure claimed in the following claims.

What is claimed is:
 1. An apparatus of controlling an electronic parkingbrake, comprising: an electric parking brake (EPB) configured togenerate target clamping force; an information collector configured tocollect a primary warning signal and a primary demanded deceleration byinteroperating with an advanced emergency brake system (AEBS); and acontroller configured to operate the EPB to perform a preparationprocess for braking when the primary warning signal is collected andperform braking until a primary actual deceleration that corresponds tothe primary demanded deceleration is measured when the primary demandeddeceleration is collected.
 2. The apparatus of controlling an electronicparking brake according to claim 1, wherein the EPB includes a brakeshoe, a brake drum, and a brake operating motor.
 3. The apparatus ofcontrolling an electronic parking brake according to claim 2, whereinthe controller is configured to operate the EPB to allow the brake shoeto approach a contact point of the brake drum, as the preparationprocess.
 4. The apparatus of controlling an electronic parking brakeaccording to claim 3, wherein the controller is configured to operatethe EPB based on the brake shoe moving further due to inertia when acurrent is blocked due to characteristics of the brake operating motor.5. The apparatus of controlling an electronic parking brake according toclaim 1, wherein the primary actual deceleration is the primary demandeddeceleration or less.
 6. The apparatus of controlling an electronicparking brake according to claim 5, wherein the primary actualdeceleration is about 90% of the primary demanded deceleration.
 7. Theapparatus of controlling an electronic parking brake according to claim1, wherein the controller is configured to operate the EPB to performbraking until a secondary actual deceleration that corresponds to asecondary demanded deceleration is measured when the secondary demandeddeceleration is collected.
 8. The apparatus of controlling an electronicparking brake according to claim 7, wherein the secondary actualdeceleration is the secondary demanded deceleration or less.
 9. Theapparatus of controlling an electronic parking brake according to claim8, wherein the secondary actual deceleration is about 90% of thesecondary demanded deceleration.
 10. The apparatus of controlling anelectronic parking brake according to claim 7, wherein the controller isconfigured to operate the EPB to perform a slow ramp up (SRU) functionwhen the secondary actual deceleration is converged within a thresholdrange in relation to the secondary demanded deceleration.
 11. Theapparatus of controlling an electronic parking brake according to claim10, wherein the controller is configured to operate the EPB to stop theSRU function based on a request from a vehicle dynamic control (VDC).12. A method of controlling an electronic parking brake, comprising:collecting, by an information collector, a primary warning signal froman advanced emergency brake system (AEBS); performing, by a controller,a preparation process for braking; collecting, by the informationcollector, a primary demanded deceleration from the AEBS; and operating,by the controller, an electric parking brake (EPB) to perform brakinguntil a primary actual deceleration that corresponds to the primarydemanded deceleration is measured.
 13. The method of controlling anelectronic parking brake according to claim 12, wherein the EPB includesa brake shoe, a brake drum, and a brake operating motor.
 14. The methodof controlling an electronic parking brake according to claim 13,wherein the controller is configured to operate the EPB to allow thebrake shoe to approach a contact point of the brake drum, as thepreparation process.
 15. The method of controlling an electronic parkingbrake according to claim 14, wherein the controller is configured tooperate the EPB based on the brake shoe moving further due to inertiawhen a current is blocked due to characteristics of the brake operatingmotor.
 16. The method of controlling an electronic parking brakeaccording to claim 12, wherein the primary actual deceleration is theprimary demanded deceleration or less.
 17. The method of controlling anelectronic parking brake according to claim 12, further comprising:collecting, by the information collector, a secondary demandeddeceleration from the AEBS; and operating, by the controller, the EPB toperform braking until a secondary actual deceleration that correspondsto the secondary demanded deceleration is measured.
 18. The method ofcontrolling an electronic parking brake according to claim 17, whereinthe secondary actual deceleration is the secondary demanded decelerationor less.
 19. The method of controlling an electronic parking brakeaccording to claim 17, further comprising: operating, by the controller,the EPB to perform a SRU function when the secondary actual decelerationis converged within a threshold range in relation to the secondarydemanded deceleration.
 20. The method of controlling an electronicparking brake according to claim 19, wherein the controller isconfigured to operate the EPB to stop the SRU function based on arequest from a vehicle dynamic control (VDC).